Ok, no problem, actually though, I think some of the results in the search strings I showed do go into that, ( the last 3 links, in my post), if you don't find what you need, or have trouble understanding parts of what the say, when you clarify what parts you do not understand, some one should be able to help.

Well, it is a pretty complicated deal, and nothing clear exact step by step, but some hints, in the search results there still is a lot of info I have not read,and you will need to weed through it all, read them,... or hire a expert that just "knows" how, give the tech access and all the details they ask for and need.1st off, myself, I have never tried this, all though at one time I was in a situation where I thought I would try, but when I read some information and saw what risks are involved, and how complicated it could be, well I contacted a person that takes care of the servers, and he did what I needed to do manually, for me. Anyway, in this link: https://wiki.debian.org/PXEBootInstall

During the installation you will need a network boot server.

As there are no fiducial boot servers out in the wild, you need to set up your own. This is considerably more complicated than installing Debian from CD (shorthand for CD or USB or ...). Normally, network booting is only used if there is really no way to boot from CD. If booting from CD fails this may be due to BIOS problems that will equally prevent network booting (typical troubleshooting attempts include switching off secure booting, switching from UEFI to legacy boot mode, and similar).In the Web, several articles can be found that describe in more or less detail how to setup a network boot server. They all have the same weakness: You are required to execute a long list of instructions without getting any feedback before the very end of the procedure when you try to boot. If it works, fine. If not, debugging will become very very difficult. Therefore in the following we break down the procedure into steps that can be debugged separately.

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Activate PXE boot

Setup the BIOS boot menu of the Client to boot from the network.Reboot. On most sytems this produces an output that contains the Client's MAC address. Then, it will fail with PXE-E53: no boot filename received.Note the MAC address, it will be helpful for interpreting log messages.On many servers, it is also possible to temporary switch to PXE boot without permanently changing the BIOS settings. There will be some kind of key stroke to hit during BIOS POST. On Dell servers, F12 will do the trick (or Esc then @ from a serial or IPMI console).

Keep reading, just following somelinks is not enough, you need to read, everything , What follows what I quoted,is:

Set up DHCP server

On the Server, we need to set up a DHCP server. ----snip---

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by checkout » So how can I change the boot order remotely ? and temporarily ?

In another link , one of the many search results, there might be others that are even better, but the only way to know is by reading them. The other: https://ubuntuforums.org/showthread.php?t=2055411 Give some hint about it, in a nut shell it involves going into the grub boot menu, editing it so that it boots with what you want, again, not really simple and there are risks. You do that before re-booting, when you reboot, assuming you edited the boot menu correctly, it will boot in the order you told it to,... There still are quite a bit of details you don't give, The wiki, gives a examplethat applies to Dell servers,

On Dell servers, F12 will do the trick (or Esc then @ from a serial or IPMI console).

How ever, you do not give any harware information, So how could anyone tell you what you need to do to access the bios ? This "network", is it servers, ? or what ? . Why is it necessary to do this remotely ?, What will you do if for example you make a mistake, and it does not reboot, ? How will you power it on again ? This also does explain how and what you need to do:https://debian-administration.org/article/478/Setting_up_a_server_for_PXE_network_booting

I can not spend any more time on this myself, I have to many other things I need to do, including making a living. Supposed to be retired, but my wife spends to much money and the pension is not enough. How ever, I would suggest maybe trying to find a qualified technician, that you trust, and can afford. It is beyond the scope of this forum to recommend any in particular. I am not qualified for something like this, all though I do know a couple of guys that are, but they are not available either. Maybe some body else on this forum can help you, sorry I can't do any more.

Thx you so much for this help. I know what I'm doing is a little bit tricky.

The hardware is computers HP MP9 and HP ProLiant servers. The reason of this is because I need to deploy a new Debian and I will need to do it for each deployments. PXE Boot was a good idea at first but now I'm not so sure.

I mean, there might be others looking for a solution, and even though there aremany solutions listed when one does a search, it still would be nice if others could know what the solution is/was. It works both ways, you ask for help, you should also help in return. But in any event, no obligations,... glad to know you found a solution.